2021-06-11

Astronomers discovered an unusual globular cluster, which tells us:the Milky Way is parasitized

By yqqlm yqqlm

A spherical star cluster with abnormal speed of motion Was discovered.

getInterUrl?uicrIvZQ=42bd9fe05a40cddfa83b48ae3faf7a4a - Astronomers discovered an unusual globular cluster, which tells us:the Milky Way is parasitized

Globular star cluster NGC 5139. This is a typical globular star cluster. ESO/INAF-VST/OmegaCAM

Globular clusters are a kind of celestial bodies that are well recognized. They are essentially a large number of stars closely clustered together. They are spherical in general, so they are called globular clusters. In the center of the globular cluster, the density of stars is very high. Within a space of tens of light-years, millions of stars can be squeezed in, so that the average distance between adjacent stars is only 0.1 light-years.

So far, astronomers are in the the Milky Way Approximately 150 globular star clusters have been discovered in, most of them are located in the halo of the Milky Way. Around some very large galaxies, the number of globular clusters can be several orders of magnitude higher.

The age of stars in globular clusters is generally very old. Astronomers believe that globular clusters were born during the explosive star-making period of the early universe, and have remained basically intact to this day. Therefore, globular star clusters are often regarded as living fossils in the universe.

getInterUrl?uicrIvZQ=dccfd8fc3f5923f021493a91bdb72b82 - Astronomers discovered an unusual globular cluster, which tells us:the Milky Way is parasitized

VVV-CL160 on different bands. Minniti

The recent Chilean astronomers are at a distance from In the space not far away from the earth, a globular cluster that no one had discovered before was discovered. This globular star cluster”hides” so well that it was almost let go as an open star cluster.

This globular star cluster named VVV-CL160 has another strange feature-its self-propelled speed, that is, its flying speed in space is very high, high To the extent it is almost abnormal.

Astronomers actually noticed this cluster in 2014. But at that time people thought it was just an ordinary open star cluster. At that time, people estimated that the distance between it and the earth was 17,100 light-years, and the metal was rich in -0.72, formed in approximately 1.6 billion years ago.

But astronomers who have obtained the latest data recently discovered that the stars in this cluster are very concentrated, which is actually a globular cluster.

New data shows that the distance between VVV-CL160 and the earth is 13,000 light-years, and its core radius is about 1.43 light-years, and the outer The radius of the tide is 189 light-years. The overall luminosity of the cluster is -7.6, and the metal abundance is -1.4.

VVV-CL160 was formed much earlier than people previously thought, it was formed about 12 billion years ago.

But the strangest thing is not these, but its speed. Compared with most other globular star clusters, its speed of motion is abnormally high. The only thing that can be compared is the globular star cluster NGC 6544 in the constellation Sagittarius, and a halo star stream called Hrid.

Researchers have analyzed various parameters and speculated that VVV-CL160 may not be an ordinary galactic globular cluster, but an extension of the Hrid halo star stream.

In other words, VVV-CL160 may actually be part of Hrid’s halo stream. If so, then the length of the Hrid halo star stream is much longer than previously thought. And its star size is large enough to be called a dwarf galaxy, an elongated galaxy, Dwarf galaxies that have been”parasitic” in the Milky Way for many years.

getInterUrl?uicrIvZQ=5694589fb0082515c94ef3a8f1e0d577 - Astronomers discovered an unusual globular cluster, which tells us:the Milky Way is parasitized

NGC 6544 in the constellation Sagittarius is also a globular cluster with an abnormal speed of self-propagation. DSS2

Reference
Discovery of a new nearby globular cluster with extreme kinematics located in the extension of a halo stream
https://arxiv.org/abs/2106.01383